body, html
    line-height :1
    font-weight: 200
    font-family: 'PingFang SC','STHeitiSC-Light','Helvetic-Light',Arial, Helvetica, sans-serif

border-1px($color)
    position:relative
    &:after
        display block
        position absolute
        left 0px 
        bottom 0
        width 100%
        border-top 1px solid $color
        content ''
bg-image($url)
    background-image: url($url + "@2x.png")
    @media (-webkit-min-device-pixel-ratio: 3),(min-device-pixel-ratio: 3)
        background-image: url ($url + "@3x.png")
.clearfix
  display: inline-block
  &:after
    display: block
    content: '.'
    height: 0
    line-height: 0
    clear: both
    visibility: hidden
border-none()
  &:after
    display: none
.clearDiv
    clear both